On May 19, the LIGO Scientific Collaboration (LSC) will dedicate their second-generation gravitational-wave detectors (aLIGO) in a ceremony at the Hanford detector site. Researchers at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) in Hannover and Potsdam, Germany, have made significant contributions in several key areas: custom-made high-power laser systems required for the high-precision measurements, efficient data analysis methods running on powerful computer clusters, and accurate waveform models to detect gravitational waves and extract astrophysical information. The AEI is a leading partner in the international gravitational-wave science community, and its researchers keep pushing the boundaries of science on the way to the first direct detection of gravitational waves.
This will open a new window to the otherwise invisible “dark” side of the Universe and mark the beginning of gravitational-wave astronomy. Gravitational waves are ripples in space-time that are emitted by cataclysmic cosmic events such as exploding stars, merging black holes and/or neutron stars, and rapidly rotating compact stellar remnants. These waves were predicted in 1916 by Albert Einstein as a consequence of his general theory of relativity, but have never been observed directly. At their design sensitivity, the aLIGO instruments should detect multiple gravitational-wave events each year.
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Despite earlier reports of a possible detection, a joint analysis of data from ESA’s Planck satellite and the ground-based BICEP2 and Keck Array experiments has found no conclusive evidence of primordial gravitational waves.
The Universe began about 13.8 billion years ago and evolved from an extremely hot, dense and uniform state to the rich and complex cosmos of galaxies, stars and planets we see today.
An extraordinary source of information about the Universe’s history is the Cosmic Microwave Background, or CMB, the legacy of light emitted only 380 000 years after the Big Bang.
ESA’s Planck satellite observed this background across the whole sky with unprecedented accuracy, and a broad variety of new findings about the early Universe has already been revealed over the past two years.
But astronomers are still digging ever deeper in the hope of exploring even further back in time: they are searching for a particular signature of cosmic ‘inflation’ – a very brief accelerated expansion that, according to current theory, the Universe experienced when it was only the tiniest fraction of a second old.
According to Einstein, whenever massive objects interact, they produce gravitational waves — distortions in the very fabric of space and time — that ripple outward across the universe at the speed of light. While astronomers have found indirect evidence of these disturbances, the waves have so far eluded direct detection. Ground-based observatories designed to find them are on the verge of achieving greater sensitivities, and many scientists think that this discovery is just a few years away.
Catching gravitational waves from some of the strongest sources — colliding black holes with millions of times the sun’s mass — will take a little longer. These waves undulate so slowly that they won’t be detectable by ground-based facilities. Instead, scientists will need much larger space-based instruments, such as the proposed Laser Interferometer Space Antenna, which was endorsed as a high-priority future project by the astronomical community.
A team that includes astrophysicists at NASA’s Goddard Space Flight Center in Greenbelt, Md., is looking forward to that day by using computational models to explore the mergers of supersized black holes. Their most recent work investigates what kind of “flash” might be seen by telescopes when astronomers ultimately find gravitational signals from such an event.
Sensors destined for ESA’s LISA Pathfinder mission in 2014 have far exceeded expectations, paving the way for a mission to detect one of the most elusive forces permeating through space – gravitational waves.
The Optical Metrology Subsystem underwent its first full tests under space-like temperature and vacuum conditions using an almost complete version of the spacecraft.
The results exceeded the precision required to detect the enigmatic ripples in the fabric of space and time predicted by Albert Einstein – and did it by two to three times.